[PATCH v12 net-next 13/15] tcp: accecn: add tcpi_ecn_mode and tcpi_option2 in tcp_info
From: <hidden>
Date: 2026-01-28 14:35:10
Also in:
bpf, linux-doc, linux-kselftest
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
From: Chia-Yu Chang <redacted> Add 2-bit tcpi_ecn_mode feild within tcp_info to indicate which ECN mode is negotiated: ECN_MODE_DISABLED, ECN_MODE_RFC3168, ECN_MODE_ACCECN, or ECN_MODE_PENDING. This is done by utilizing available bits from tcpi_accecn_opt_seen (reduced from 16 bits to 2 bits) and tcpi_accecn_fail_mode (reduced from 16 bits to 4 bits). Also, an extra 24-bit tcpi_options2 field is identified to represent newer options and connection features, as all 8 bits of tcpi_options field have been used. Signed-off-by: Chia-Yu Chang <redacted> Co-developed-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> --- include/net/tcp_ecn.h | 11 ----------- include/uapi/linux/tcp.h | 26 +++++++++++++++++++++++--- net/ipv4/tcp.c | 8 ++++++++ 3 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/include/net/tcp_ecn.h b/include/net/tcp_ecn.h
index e01653bbf181..e9a933641636 100644
--- a/include/net/tcp_ecn.h
+++ b/include/net/tcp_ecn.h@@ -67,12 +67,6 @@ static inline void tcp_ecn_withdraw_cwr(struct tcp_sock *tp) tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR; } -/* tp->accecn_fail_mode */ -#define TCP_ACCECN_ACE_FAIL_SEND BIT(0) -#define TCP_ACCECN_ACE_FAIL_RECV BIT(1) -#define TCP_ACCECN_OPT_FAIL_SEND BIT(2) -#define TCP_ACCECN_OPT_FAIL_RECV BIT(3) - static inline bool tcp_accecn_ace_fail_send(const struct tcp_sock *tp) { return tp->accecn_fail_mode & TCP_ACCECN_ACE_FAIL_SEND;
@@ -98,11 +92,6 @@ static inline void tcp_accecn_fail_mode_set(struct tcp_sock *tp, u8 mode) tp->accecn_fail_mode |= mode; } -#define TCP_ACCECN_OPT_NOT_SEEN 0x0 -#define TCP_ACCECN_OPT_EMPTY_SEEN 0x1 -#define TCP_ACCECN_OPT_COUNTER_SEEN 0x2 -#define TCP_ACCECN_OPT_FAIL_SEEN 0x3 - static inline u8 tcp_accecn_ace(const struct tcphdr *th) { return (th->ae << 2) | (th->cwr << 1) | th->ece;
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index dce3113787a7..03772dd4d399 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h@@ -226,6 +226,24 @@ enum tcp_ca_state { #define TCPF_CA_Loss (1<<TCP_CA_Loss) }; +/* Values for tcpi_ecn_mode after negotiation */ +#define TCPI_ECN_MODE_DISABLED 0x0 +#define TCPI_ECN_MODE_RFC3168 0x1 +#define TCPI_ECN_MODE_ACCECN 0x2 +#define TCPI_ECN_MODE_PENDING 0x3 + +/* Values for accecn_opt_seen */ +#define TCP_ACCECN_OPT_NOT_SEEN 0x0 +#define TCP_ACCECN_OPT_EMPTY_SEEN 0x1 +#define TCP_ACCECN_OPT_COUNTER_SEEN 0x2 +#define TCP_ACCECN_OPT_FAIL_SEEN 0x3 + +/* Values for accecn_fail_mode */ +#define TCP_ACCECN_ACE_FAIL_SEND BIT(0) +#define TCP_ACCECN_ACE_FAIL_RECV BIT(1) +#define TCP_ACCECN_OPT_FAIL_SEND BIT(2) +#define TCP_ACCECN_OPT_FAIL_RECV BIT(3) + struct tcp_info { __u8 tcpi_state; __u8 tcpi_ca_state;
@@ -316,15 +334,17 @@ struct tcp_info { * in milliseconds, including any * unfinished recovery. */ - __u32 tcpi_received_ce; /* # of CE marks received */ + __u32 tcpi_received_ce; /* # of CE marked segments received */ __u32 tcpi_delivered_e1_bytes; /* Accurate ECN byte counters */ __u32 tcpi_delivered_e0_bytes; __u32 tcpi_delivered_ce_bytes; __u32 tcpi_received_e1_bytes; __u32 tcpi_received_e0_bytes; __u32 tcpi_received_ce_bytes; - __u16 tcpi_accecn_fail_mode; - __u16 tcpi_accecn_opt_seen; + __u32 tcpi_ecn_mode:2, + tcpi_accecn_opt_seen:2, + tcpi_accecn_fail_mode:4, + tcpi_options2:24; }; /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a0569e89f580..d8405b419ce0 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c@@ -4379,6 +4379,14 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) if (tp->rto_stamp) info->tcpi_total_rto_time += tcp_clock_ms() - tp->rto_stamp; + if (tcp_ecn_disabled(tp)) + info->tcpi_ecn_mode = TCPI_ECN_MODE_DISABLED; + else if (tcp_ecn_mode_rfc3168(tp)) + info->tcpi_ecn_mode = TCPI_ECN_MODE_RFC3168; + else if (tcp_ecn_mode_accecn(tp)) + info->tcpi_ecn_mode = TCPI_ECN_MODE_ACCECN; + else if (tcp_ecn_mode_pending(tp)) + info->tcpi_ecn_mode = TCPI_ECN_MODE_PENDING; info->tcpi_accecn_fail_mode = tp->accecn_fail_mode; info->tcpi_accecn_opt_seen = tp->saw_accecn_opt; info->tcpi_received_ce = tp->received_ce;
--
2.34.1